1. Technical Field
The present invention relates to a headlight provided to a vehicle such as an automobile, and particularly relates to a headlight with which early detection of a pedestrian or the like ahead of the vehicle is possible even with a passing beam having a cutoff line.
2. Related Art
A headlight of a vehicle such as an automobile projects light emitted from a light source such as, for instance, an incandescent light bulb, discharge lamp, and LED with a projection optical system such as a projector and a reflective optical system such as a reflector.
With such a headlight, switching is possible between a driving beam (high beam) for use during normal driving and a passing beam (low beam) for use when passing an oncoming vehicle.
In order to prevent glare that dazzles an oncoming driver, a cutoff line is formed in a predetermined range at the upper edge of a light distribution pattern for the passing beam, such that light is substantially not radiated above the cutoff line.
In such a headlight, it is known that a desired light distribution pattern is formed through collaborative use of a plurality of light sources or optical systems.
For instance, Japanese Unexamined Patent Application Publication (JP-A) No. 2011-3515 describes that a main light distribution pattern or the like having a cutoff line is formed by a projector unit and a diffused light distribution pattern is formed by a reflector unit.
Japanese JP-A No. 2011-161035 describes that apart of abeam emitted by a light source of a projector unit is guided to a reflector by a mirror member to illuminate a shoulder or the like on the driving lane side.
JP-A No. 2001-195910 describes that an auxiliary light distribution pattern for a passing beam from a projector unit is formed by an auxiliary reflector.
In order to prevent glare that dazzles an oncoming driver or the like, it is required that a cutoff line be provided in a predetermined range in the horizontal direction for a passing beam (so-called low beam) of a vehicle headlight. Within a predetermined angle range ahead of the vehicle in the horizontal direction, light distribution above the cutoff line is restricted.
However, with such a passing beam, there are cases where the visibility of a pedestrian or the like beside a driving lane ahead of the vehicle is lower than with a driving beam (so-called high beam), rendering early detection of the pedestrian or the like difficult.